D.C. transit system Crossword Clue

 The answer to the crossword clue "D.C. transit system" is METRO.

The Washington Metro, also known as Metrorail, is a rapid transit system serving the Washington metropolitan area in the United States. It is administered by the Washington Metropolitan Area Transit Authority (WMATA), which also operates the Metrobus service under the Metro name. Opened in 1976, the network now includes six lines, 98 stations, and 129 miles (208 km) of route.

The Metro is the second busiest rapid transit system in the United States, after the New York City Subway. It serves over 700,000 riders on a typical weekday.

The Metro is a popular way to get around the Washington metropolitan area. It is convenient, affordable, and environmentally friendly. The Metro is also a great way to see the sights of Washington, D.C., as many of the stations are located near popular tourist destinations.